De novo synthesis of fatty acids will be studied using lung slices obtained from rats fed regular chow, fat free supplemented with 4% safflower oil, or fat free diet supplemented with 4% tripalmitin, as well as from adult rats made diabetic with streptozotocin and their fetuses. Incorporation of label from 3H2O, 1-14C-acetate, or other precursors, into tissue total fatty acids, triglyceride fatty acids and phospholipid fatty acids will be examined and the degree of unsaturation of the newly synthesized fatty acid determined. Similar studies will be performed using type II cells isolated from lungs of these groups of animals. Additionally, serial studies will be carried out on the fatty acid composition of lecithins obtained by bronchial lavage from patients with ARDS secondary to trauma, head injury or sepsis. These findings will be correlated with physiologic measurements of pulmonary function and lung mechanics.